Why would anyone spend $7,000 on a tote bag? Maybe they’re using luxury goods to express who they are or convey their social status. Maybe outrageous totes make certain shoppers feel less empty inside. Or perhaps, as a study in the September issue of Journal of Consumer Research reveals, that person is a woman using expensive items to let other ladies know that her man is taken.

Two marketing researchers at the University of Minnesota conducted five experiments on 649 women, either online or in person, to answer a complicated question: While studies have shown that men use wildly pricey products to attract romantic partners, what role do those goods play when it comes to females and relationships? Yajin Wang and Vladsa Griskevicius hypothesized that the ladies use such possessions not to entice mates but to signal that their partner is especially devoted to them—so other women know that they had best move along.

In an additional pilot study, 47 out of 76 women (about 62%) said that if they went out with their man while wearing fancy clothes and jewelry, other women would think their beau cared about them more. When the researchers primed other females to feel jealous, that increased ladies’ interest in showing off luxury products with big, bold logos. And they found that affair-prone women were less likely to pursue a taken man if the “mate poachers” knew the man had bought luxury goods for his date. In short, they found evidence that women do indeed believe designer things will ward off potential threats to their relationship, and that it works.

There is a caveat: their results only held true if it appeared the high-end chattel was purchased by the man. It may be old-fashioned, but when women were given no information about who paid for luxury items in hypothetical scenarios, they would assume that the man forked up at least half the cost. If females were told that another woman bought her own fancy baubles, their deterrent power was lost. That’s because, the researchers say, gifted Prada handbags and the like symbolize “a man’s willingness to spend and invest resources in a mate,” which “is considered a strong indicator of his commitment to the relationship.” And “female mate poachers,” they write, “are less likely to pursue a committed man.”

In turn, they say, it all goes back to evolutionary habits. Males are focused on mating, while females are more interested in making sure their partners devote enough resources to take care of her and her offspring. If those resources are already tied up elsewhere, that man may become a less likely target of other females’ advances—hence, the lady has every incentive to put her finest doodads on display.